I just bought a returned LSS from Sweetwater. I had it about 2 weeks and lost the 5Y3 tube. I contacted Sweetwater, stating in my message that I suspect that is why it was returned. I received phone call promptly from the service tech. He confirmed that was the reason for return, but he made the resistor update when it was returned. He told me that Mesa has suggested another change to lower the voltage.
He also said the he and Mesa were working on a permanent fix for this situation. One thing he came up with is to use a 5R4G rectifier tube. They are designed to handle higher voltage without overloading the power tubes. Mesa agreed with his choice and has okay'ed the use of this type of tube. I placed an order for a 5R4G tube and it should be here any day. I will report back in a few weeks. Hopefully this will hold up. I love the amp and don't want to unload it.
I had on hand a NOS 5U4G & NOS 5AR4, but didn't want to try either until I spoke with someone. The Sweetwater tech told me that using either would have increased the plate voltage to the power tubes too much and would have lead to premature tube failure, so I'm happy I didn't do that.